Electron-Density Measurements in an Electron Cyclotron Resonance Plasma

Abstract

Electron density in an electron cyclotron‐heated plasma is determined by two methods. The first is by perturbation of the resonant frequency of fundamental modes of the cavity in which the plasma is contained. It is seen that for the TE_{L in} (L > 0) class of modes, the resonant frequency increases, decreases and then increases as electron density is increased. The second method utilizes microwave transmission cutoff as the steady‐state density of the plasma is such that the plasma frequency of the electrons exceeds the transmitted signal frequency.